Purification of illuminating or coke-oven gases and the like



April 21,1931. CLAUDE 1,801,903

PURIFICATION OF ILLUMINATING OR COKE OVEN GASES AND THE LIKE Filed Oct. 20, 1924 a M 4 k 1 r AM...

Lat:- '3 10 mvflvzzm AT/WHNEY Patented Apr. 21, 1931 UNITED STATES PATENT OFFICE GEoRGEs CLAUDE, or PARIS, rRANcE, AssIGNoR T0 LA socinrfi LAIR neuron, soorn'r'n ANONYME roUR LET'UDE ET LEXPLOITATION DES PROO'ED'ES GEORGES CLAUDE, or PARIS, FRANCE PURIFICATION OF ILLUMINATING OR COKE-OVEN GASES AND THE LIKE Application filed October 20, 1924, Serial No.

This invention relates to the preliminary treatment or purification of illuminating or coke oven gases and the like intended to be subjected to partial liquefaction for the separation of their various constituents, and has for its particular object the extraction of ethylene and the removal by its aid of certain other hydrocarbons and condensable impurities which it is desired to take out of the gases before they are subjected to the main liquefaction and rectification in the separating apparatus proper.

When the proportion of ethylene present in ordinary illuminating or coke oven gases is especially high, in consequence of thequality of the coal used or the conditions of distillation, this ethylene may give rise to difliculties in the operation of the processes for the extraction of the hydrogen from these gases by means of liquefaction. Even when this ethylene is concentrated by rectification in the lower part of the exterior compartment of the vaporizer of the separating apparatus prop-er it may be present in such considerable quantity as to deterimentally affect the temperature of the liquids in this compartment and the liquefaction of the ases which are subjected to the cooling action of this li uid in their passage through the vaporizer.

n the rocess described in the specification of British Patent No. 195598 a large part of this ethylene was prevented from reaching the separating apparatus proper by partially condensing. it in the temperature exchangers preceding the said separating apparatus, and the main purpose of the present invention is toimprove the conditions .of this condensation. Instead therefore of condensing in the temperature exchanger or exchangers a series of different liquids 1n accordance with their respective condensabilities and extracting these liquids which are successively formed at their actual points of formation where they each contain the relatively small proportion of ethylene which is liquefied at the point 1n question, it is sought by means of the present process to bring about an enrichment in ethylene of these liquids.

According to the present invention the 744,823, and in France November 20, 1923.

illuminating or coke oven gas or similar gases intended to be subjected to partial liquefaction and rectification for the separation of their constituents, wherein the gases to be treated are subjected to progressive cooling in temperature exchangers preceding the partial liquefaction or separating apparatus proper, is characterized in that the extraction of ethylene and the removal by its aid of certain impurities are effected by circulating the gases to-be treated in an upwarddirection through the zone where the ethylene liquefies and up to the region where considerable liquefaction of the methane commences fully with reference to the accompanying drawing which illustrates by way of example a diagrammatic sectional view of one form of apparatus for carrying out the present process.

A, B and C represent three temperature exchangers in series preceding the separating apparatus proper, from which latter the separated gases, comprising hydrogen on the one hand and carbon monoxide and methane on the other. hand, are delivered respectively through the inlet pipes 1 and 2 into the tubes of the temperature exchanger G, through which they pass from the bottom to the top, thereafter passing by way of the pipes 5 and 6 into the temperature exchanger B, which they traverse from the top to the bottom, and then passing through the pipes 9 and 10 into the temperature exchanger A which they traverse from the bottom to the top, finally escaping by the outlets 15 and-16.

The gases to be treated are delivered through the inlet 11 around the tubes of the 50 process for the preliminary purification 0f -temperature exchanger A an circulate m The liquids which condense during the passage of the gases to be treated through the exchanger A comprise the most readily condensable substances which have escaped from the preliminary purifying devices, and this exchanger may be provided with collectors for condensed liquids as has been described in British patent specification No. 195598! The exchanger C is a smaller one than the others, in view of the very low temperature for example l40 C; attained by the gases when they reach the top of the exchanger B; this temperature is not sufiicient, however, to effect liquefaction of the methane to. a very great extent. At this temperature the ethylene, on the contrary, is liquefied almost entirely, the proportion of methane carried with it increasing towards the top of the exchanger B. The-liquids produced flow back however towards the bottom of the exchanger B under'the action of gravity, and encounter, during this reflux, regions which become gradually warmer, so that the methane evaporates and the liquids become richer and richer in ethylene. If the liquids were permitted to flow back until they reached too warm a region, the ethylene would revaporize in its turn; in order to prevent this there is arranged at a suitable point a liquid collector K which receives the suitably enriched liquids, which are drawn off, preferably in a continuous manner, by means of the tap r. These liquids consist for the main partof ethylene, accompanying which there are a certain number of other dissolved hydrocarbons, such as ethane, acetylene, etc., which are contained in the. treated gaseous mixture in such small quantities as to be considered as, impurities. Arrangements may be made to recover the cold of these liquids.

The position of the collector K is determined by experiment, several collectors placed at different heights of the exchanger being provided, and the most suitable one according to the particular conditions obtaining being chosen. As the hydrogen which is delivered from the separating apparatus is colder than the mixture of carbon-monoxide and methane, the latter may if desired be introduced into the system of exchangers through the pipe 6 instead of the pipe 2.

I claim as my invention: 1. A process for the preliminary purification by cold of gaseous mixtures containing hydrogen, such as coal gas or coke oven gas,

intended to be subjected to partial liquefaction, which comprises circulating the compressed gaseous mixturev in a substantiallyupward direction while progressively cooling it, progressively liquefying substantially all the ethylene, removing the gaseous residue when only some methane has been liquefied, allowing the liquefied portions to travel back in contact with and in the opposite direction to the ascending gaseous mixture, and remov- .ing the ethylene-containing liquid at the point where it contains substantially all the dissolved hydrocarbons.

2. A process for the preliminary purification by cold of gaseous mixtures containing hydrogen, such as coal gas or coke oven as, intended to be subjected to partial lique action, comprising the steps of passing the compressed gaseous mixture through a temperature-exchanger in an upward direction for liquefying the greater part of the ethylene and allowing the liquefied portions formed to travel back into contact with and in the opposite direction to the ascendin gaseous mlxture for dissolving therein hy rocarbons such as ethane and acetylene;

3. A process for the preliminary purification by cold of gaseous mixtures containing hydrogen, such as coal gas or coke oven as, intended to, be subjected to partial lique action, comprising the steps of passing the compressed gaseous mixture first through a temperature-exchanger in a downward direction while collecting the liquids formed, then through a second temperature-exchanger in an upward direction for liquefying the greater part of the ethylene and thereby dissolving in it hydrocarbons such as ethane and acetylene and finally through a third temperature-exchanger in a downward direction,

-whence the gaseous mixture is sent to the hydrogen-separating apparatus proper.

4. A process for the preliminary purification by cold of gaseous mixtures containing hydrogen, such as coal gas or coke oven gas, intended to be subjected to partial liquefaction, which consists in passing the compressed gaseous mixture first through a temperature-exchanger in a downward direction while collecting the liquids formed, then through a second temperature-exchanger in an upward direction for liquefying the greats er part of the ethylene and thereby dissolving in it hydrocarbons such as ethane and acetylene and finally through a third temperature-exchanger in a downward direction, subjecting the remaining gaseous residue to a hydrogen-separating process by liquefying substantially all the gases except hydrogen, circulating the separated hydrogen in counter-current successively through the third, second and first temperature-exchangers, and circulating the other separated constituents in counter-current successively through the second and first temperature-exchangers.

5. A processfor the purification of gaseous mixtures obtained by the distillation of coal, which comprises the steps of progressively cooling the gaseous mixture down to substantially the temperature of liquefaction of methane while circulating the mixture in a substantially-upward direction, allowing the liquids progressivelyformed to travel back in contact with the ascending gaseous mixture and removing the ethylene-containing liquid at the point where it contains substantially all the dissolved hydrocarbons.

In testimony whereof I aflix my signature.

GEORGES CLAUDE. 

